The present invention generally relates to the field of impact crushers and, more particularly, to a vertical shaft impactor apparatus with improved designs for reducing its size and enhancing the accessibility and replaceability of components for maintaining the apparatus.
Impact crushing apparatuses are known and employed in various industries for reducing materials such as rock, concrete, brick, stone, and other materials into smaller shapes and sizes for further use or disposal of. In a typical impact crushing apparatus, materials are fed into a chamber and onto a rotating feed disk. The material is thrown from the center of the rotating feed disk at high speeds against an impact surface, where due to the centrifugal forces, the material is broken into smaller pieces. Generally, the rotating feed disk includes at least one impeller shoe for throwing the material against anvils radially positioned about the feed disk.
Impact crushing apparatuses are generally very large and consume significant floor space. In addition, an exemplary crushing apparatus includes a drive unit, such as an electric motor, required to rotate the feed disk. The electric motor usually has to be positioned near the feed disk and attached to the housing that encloses the chamber to tension drive belts and other drive components. This further increases the size of the space needed for the crushing apparatus. The drive unit is connected to and drives a shaft, which in turn is connected to the feed disk.
These apparatuses also present maintenance difficulties due to their size and configuration. For example, replacing a worn impeller shoe requires in many instances removing or lifting the lid of the apparatus, disengaging the rotating feed disk or rotor assembly from inside the housing, and then removing and replacing the impeller shoe. Additionally, replacing a worn anvil may require a person to remove the lid of the housing and reach over the top of the chamber to gain access to the anvil ring that holds the anvils. The anvil ring must then be removed before the worn anvil can be removed and replaced. Therefore, replacing an impeller shoe and/or anvil requires the apparatus to be opened and this presents additional disadvantages, such as subjecting the person to injury from sharp debris inside the chamber and delaying the crushing operation for maintenance.
The components of these impact crushing apparatuses that are exposed to the flow of material are subject to wear, which may be caused by abrasion, grinding, decomposition, impact, and the like. At least one surface of the impeller shoe makes contact with the material and requires replacement or maintenance depending on the amount of use. This can be expensive and increase the amount of downtime associated with the crushing operation.
In addition to wear, the impeller shoes known in the art are securely fixed to a bracket in the rotor assembly. In this design, the mass of the shoe is not centered on the bracket. As a result, a large centrifugal force acts on the mass of the shoe due to the high rotational speeds. With the mass of the shoe not being centered on the bracket, this offset acts like a lever arm for the centrifugal force acting on the mass of the shoe to induce a bending moment on the bracket. The bending moment asserts large stresses on the bracket and thus limits the strength of the rotor and the speeds the rotor can handle. Additionally, the bending moment can eventually distort the bracket.
Based on at least these reasons, there is a need to improve the design and configuration of the impact crushing apparatus. More specifically, there is a need for an impact crushing apparatus that is small and easier to maintain and has components that wear more favorably and are easier to replace.